From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3EEDBC636D6 for ; Thu, 2 Feb 2023 16:25:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232145AbjBBQZX (ORCPT ); Thu, 2 Feb 2023 11:25:23 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37866 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230424AbjBBQZS (ORCPT ); Thu, 2 Feb 2023 11:25:18 -0500 Received: from mail-wm1-x32d.google.com (mail-wm1-x32d.google.com [IPv6:2a00:1450:4864:20::32d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 30958233C3 for ; Thu, 2 Feb 2023 08:25:06 -0800 (PST) Received: by mail-wm1-x32d.google.com with SMTP id n28-20020a05600c3b9c00b003ddca7a2bcbso1839935wms.3 for ; Thu, 02 Feb 2023 08:25:06 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=xKkQ/MGYg75Krl7zSnOxIL9rasEvYWJbhYfIJlw/MJE=; b=VoppvjbP97+x6wLZbumvfPPdxVNlasPUlw9jNftlxNfy8mPVVNtmggL+2ShSgBe8M2 5ENqCsAlY6CeslsI5+h+Sv/gTCpznE1L072jzeDK/jPPuFSjZNEWrqeouJpUGmcOO5qW 0ovjNG1NcTgB+qh663kL+4F1Ub80QHJtnAD7FmpCLDp44UjbHbeExNtVn/yhpCfeuZZf gkgSPU7IRjqoEOlCBkQF5otqWDtojKUYTyquE9G/hOsKpw7RS8mwbh5A6tsm77niUfDg 9NPnTcOgzkiNpJg3ZpE5DCi3sAf0h/5qOPANnFLRr5aHGzCL/gyfhRl68fs0fmBkAu69 xnrQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=xKkQ/MGYg75Krl7zSnOxIL9rasEvYWJbhYfIJlw/MJE=; b=mTlkZcbdnh4m8a2i72blANxYDVroqpy7poityXp8R3ubgHzva7gYihMMV9PWDhmmAI pphFII43sRzqwKL3NZP31g3vKffrG2Cn/68iSy5YDgZEQn8WmUiqiMBe7/QNNJiAicW7 BzQlF++3iUCjohThDSOS6ALHpkHqkceAHXSou3yh3zn8OCNUVo+4cNrgk8gDxsOnkYtc jiDFLkGrhr+9tubjLwfn+NTcUk5aI1EeLxID0T1OZGsTLRViiUKtHwc3yp/Xb26s2kBL yd6/+KWJGMx6/GZ4JJz37Xmlsa2d8ECGt4RhTW9s0Ta3XIhrms81Hk2nfelpNxBFfff6 U58w== X-Gm-Message-State: AO0yUKVs2KhOzXYOV2iuYnRNJKiLFlTvKsctH0pA+hUAK8TtfoTJI+4I MlNdDpTg/thmIS+QdYPROG45rw== X-Google-Smtp-Source: AK7set8aBQAyjofXakT1skJQOIhl0iX3vO6X+TF2rtqyHnfL/CNseXBsu8Llf7cxLMReWw7evMX2lg== X-Received: by 2002:a05:600c:4e55:b0:3d9:e5d3:bf with SMTP id e21-20020a05600c4e5500b003d9e5d300bfmr6521824wmq.32.1675355104701; Thu, 02 Feb 2023 08:25:04 -0800 (PST) Received: from [192.168.1.109] ([178.197.216.144]) by smtp.gmail.com with ESMTPSA id y10-20020a05600c364a00b003daf7721bb3sm5084687wmq.12.2023.02.02.08.25.03 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 02 Feb 2023 08:25:04 -0800 (PST) Message-ID: <7ed270eb-decc-3a5d-589f-bf8175fac0d3@linaro.org> Date: Thu, 2 Feb 2023 17:25:02 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.7.1 Subject: Re: [PATCH] dt-bindings: mmc: Add cap-aggressive-pm property Content-Language: en-US To: Ulf Hansson , Hermes Zhang Cc: Rob Herring , Krzysztof Kozlowski , kernel@axis.com, linux-mmc@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org References: <20230129023630.830764-1-chenhuiz@axis.com> From: Krzysztof Kozlowski In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/02/2023 15:59, Ulf Hansson wrote: > On Tue, 31 Jan 2023 at 17:57, Krzysztof Kozlowski > wrote: >> >> On 30/01/2023 07:54, Hermes Zhang wrote: >>> On 2023/1/29 18:58, Krzysztof Kozlowski wrote: >>>> On 29/01/2023 03:36, Hermes Zhang wrote: >>>>> This commit add a new property: cap-aggressive-pm to enable the >>>> Do not use "This commit/patch". >>>> https://elixir.bootlin.com/linux/v5.17.1/source/Documentation/process/submitting-patches.rst#L95 >>> >>> Done >>> >>>>> MMC_CAP_AGGRESSIVE_PM feature for (e)MMC/SD power saving. >>>> Why this is a property suitable for DT? IOW, why this isn't enabled always? >>> >>> This property will benfit for the power consumption, but it also may >>> degradation in performance as it will prevent the >>> >>> the card from executing internal house-keeping operations in idle mode. >>> So it's better to config it from DT. >> >> Why? DT is not for policy. How you described it, this is policy or >> system tuning choice thus the job for Linux (OS), not for DT. So I will >> repeat - why this property fits the purpose of DT (describe the hardware). >> > > I guess the HW perspective here, is that it might not fit all > platforms nor the actual eMMC/SD card to support this feature. > However, it still seems like a policy rather than a strict HW > constraint. > > Perhaps there is a way to figure out in the host driver, to > conditionally set the MMC_CAP_AGGRESSIVE_PM for the host, when needed > instead? What also worries me is that there is no user of this property: no DTS, no driver, so it is tricky to deduct out when it is applicable. Anyway things which might be obvious for the submitter, might not be for the reviewer, thus I would really like to see justification why different boards (or memories) need this property. Best regards, Krzysztof